Ki and Gil will enter this room through the door at the top-left of it. It contains ten Black Vampires, three Green Snakes (which takes eight hits to kill), and one Mage (which takes five hits to kill). If Gil collected the Fork in Kitchen, he will be able to deflect the Mage's spells back at him with his sword.
The left side of this room wraps around vertically (see image to right) - and if you proceed in either direction, you will end up back where you started.
The key at the right of the room opens the aforementioned door at the top-left of the room, and that door at the top of the room is the first door in the game that is already open. Therefore, there is no key for this already open door up at the top of the room, even though it will close behind Ki and Gil.
The aforementioned door at the top-left of the room leads back to Shunned Cavern (Room Pass: SVY), and that already open door at the top of the room leads off to Water Line (Room Pass: YF7). You should remember the second of these Room Passes, as the first one is of little use to you now.
